Role of Growth Stage and Environmental Conditions in Root Rot Development and Grain Yield of Spring Wheat in the Almaty Region, Southeast Kazakhstan

In 2024, a study was conducted in the Almaty Region on 16 varieties of spring soft wheat to assess the impact of growth stages, cultivation conditions, and the severity of root rot infection on biometric parameters and crop yield. This study represents the first systematic evaluation of root rot dynamics across multiple growth stages and contrasting agronomic backgrounds in Kazakhstan. It was found that the maximum root rot prevalence (32.65%) and severity (8.78%) were observed during the tillering phase. By the harvesting phase, these indicators decreased, indicating the dynamic nature of pathogenesis. Cultivation conditions had a significant influence: Under natural conditions, disease prevalence was 26.79%, while on an infectious background, it increased to 31.60%. With fungicide application, prevalence decreased to 8.80%. Fungicide treatment proved effective in suppressing infection, though some varieties exhibited stress responses, leading to reduced productivity. The highest grain weight per plant (13.71 g) was recorded under natural conditions, while the lowest (8.31 g) was observed on the infectious background. Analysis of biometric parameters revealed significant differences between varieties in traits such as tillering capacity, stem length, spike length, and spikelet number. These findings provide a practical framework for improving integrated disease management strategies and for breeding wheat varieties adapted to regional agroecological conditions. These results highlight the importance of integrated disease management and genotype selection to sustain wheat productivity under biotic stress.